Tag Archives: borehole

Re-reading Climategate and AR4 Review Comments, I noticed an interesting discussion about handling the Law Dome O18 record – a series used in Mann and Jones (2003) and Jones and Mann (2004) with a very elevated MWP.

In recent discussions of Steig’s Antarctic reconstruction, one of the interesting statistical issues is how many principal components to retain. As so often with Team studies, Steig provided no principled reasoning for his selection of 3 PCs, statements about their supposed physical interpretation were untrue and, from some perspectives, the choice of 3 seems opportunistic. […]

Phil B writes: My day job does include parameter and state estimation using Least Squares and Kalman filtering. I have replicated several of the non-ice borehole temperature reconstructions and I’ll “share” my observations. The inversion problem boils down to finding the solution to the inconsistent set of linear equations Ax~b, where A is a skinny […]

Last year, one of the first things that puzzled me about the NAS panel report was the basis for their conclusion that there was no MWP in Antarctica. At the press conference, at about minute 60, North said: there is evidence of warmth in the record in the MWP. But as Bradley and Diaz a […]

Willis writes in: While researching ocean drill cores at the WCDC, I stumbled across Mann’s borehole data. One of the proxies used for historical temperature reconstruction is "borehole temperature", the temperature down in the ground. In 2002, Michael Mann et al. published a study called Optimal surface temperature reconstructions using terrestrial borehole data. It is […]

I know that many of you want to hear our take on Mann (and on ourselves). I’ll get to that. I want to set down some notes on the other speakers while my notes are relatively fresh in my mind; my notes on the morning session are not great, but I’ll give a gist of […]